Upgraded system to Fedora Core release 3 (Heidelberg) and had to re-install ndiswrapper and the driver.

Apparently I was using a windows driver (bcmwl5.inf) with a stack size of more than 4k. Fedora has an option to enable/disable 4k stack size. If you are running a Fedora 2.6 kernel and your machine freezes after running `modprobe ndiswrapper`, you are probably using a driver that requires a stack size greater than 4K. Try installing the 16K stack kernel update from Linuxant:

Find out the exact kernel architecture (which is not always the same as "uname -m") with the following:

# rpm -q --qf '%{ARCH}\n' kernel

Download the complete kernel RPM and install it using rpm -Uhv as root. Advanced users may want to use the patch instead, or try compiling a vanilla kernel (from http://www.kernel.org) and disabling 4K stack size (CONFIG_4KSTACKS).